Digital subscriber line (DSL) technologies can provide relatively large bandwidth for digital communications over existing subscriber lines. When transmitting data over the subscriber lines, crosstalk interference can occur between the transmitted signals over adjacent twisted-pair phone lines, for example in a same or nearby bundle of lines. Crosstalk limits the performance of some DSL technologies, such as asymmetric DSL 2 (ADSL2) and very high bit rate DSL 2 (VDSL2). Crosstalk can occur in mixed deployment scenarios, where cabinet and exchange deployed lines operate within relatively short proximity or in the same binder. Downstream power back-off (DPBO) is a static spectrum management technique that is used to reduce crosstalk. However, DPBO is typically configured to reduce crosstalk and meet a single data-rate requirement. Since the signals are typically transmitted at different rates in the lines, the DPBO does not ensure service requirements, e.g. data-rate or quality of service (QoS) requirements, for each line. Alternatively, dynamic spectrum management (DSM) techniques may be used to reduce crosstalk and achieve service requirements in multiple lines. The DSM techniques are based, on algorithms that optimize the power spectrum density (PSD) of the transmitter (e.g. modem), such as iterative waterfilling, iterative spectrum balancing, and optimal spectrum balancing. Disadvantages of such algorithms include poor performance (e.g. using iterative waterfilling) or relatively high computational complexity (e.g. using iterative spectrum balancing or optimal spectrum balancing), which causes implementation difficulties.